\documentclass[stdletter]{newlfm}

\nameto{Cousin Muscles} 
\addrto{Hogan's Alley}
\namefrom{Jerry Mouse} 
\addrfrom{Jerry's Hole}

\begin{document}
\greetto{Dear Cousin Muscles,}
\closeline{Sincerely yours,} 
\signature{J.}

\begin{newlfm}
Am having serious trouble with Tom. Need your help at once.
\end{newlfm}
\end{document}
